Thoracic Idiopathic Scoliosis: Establishing the Diagnostic Accuracy and Reference Values of Surface Topography

Study design: This is a cross-sectional prospective study of diagnostic accuracy. Objective: The aim of this study was to establish the diagnostic accuracy and cut-off points of the surface topography parameters. Methods: Seventy-seven participants of both genders, aged between 7 and 18 years old, were consecutively included. Each participant was evaluated using two randomly-chosen consecutive procedures, by means of a surface topography scanner and a Scoliometer®. In this study, the angle of trunk rotation (ATR) determined using the Scoliometer® was taken as reference. For statistical purposes, a multiple linear regression analysis was made to establish which surface topography parameters have the highest standardized beta coefficients (β). Based on the β values, two topographic parameters were chosen (apex of the curve and trunk rotation) to compose the Receiver Operating Characteristic (ROC) analysis. Results: The cut-off points for the topographic parameters were established as ATR <5° for subjects without scoliosis and ≥8° for severe scoliosis. The ROC curve analysis for the apex of the curve was significant (p<0.001) with an area under the curve (AUC) ranging between 76% [cut-off point 4.4 mm] for the subjects without scoliosis and 84% [cut-off point 9.4 mm] for the subjects with severe scoliosis. For the trunk rotation parameter, the AUC was also significant, ranging between 68% [cut-off point 1.5°, p=0.023] for subjects without scoliosis, and 73% [cut-off point 4.8°, p=0.018] for the subjects with severe scoliosis.   Conclusion: Surface topography provides adequate accuracy and can be used to evaluate the presence of the thoracic idiopathic scoliosis.